Lung imaging has historically been dominated by conventional x-ray technology. The most wide-spread imaging study in America remains the chest x-ray, with an estimated 100 million or more performed each year. Computerized tomography also delineates lung anatomy and pathology well. However, neither of these imaging techniques provides any significant insight into lung function and pathophysiology. Functional imaging of the lungs has historically been the domain of nuclear medicine. Even magnetic resonance imaging, which has allowed spectacular functional imaging of the human brain has been difficult to apply in the lung. Recent work has shown that hyperpolarized 3He, which is not radioactive and which is chemically inert, can be used as an MRI contrast agent to